One.relative_identifier(
  1 * 2,
  key: 3 / 4
) * Two.relative_identifier(
  2 / 1,
  key: 4 * 3
)
One.relative_identifier(
  1 / 2,
  key: 3 * 4
)(
  4 * 5,
  key: 6 / 7
) / Two.relative_identifier(
  2 * 1,
  key: 4 / 3
)(
  5 / 4,
  key: 7 * 6
)
One.relative_identifier key: 1 * 2
One.relative_identifier unqualified 1 / 2,
                                    key: 3 / 4
One.relative_identifier 1 * 2,
                        key: 3 * 4
